From f618466c25d43f3bae9e40920273bf77de1e1149 Mon Sep 17 00:00:00 2001
From: leochanj105 <leochanj@live.unc.edu>
Date: Mon, 19 Oct 2020 23:09:30 -0400
Subject: initial sd-vbs

initial sd-vbs

add sd-vbs

sd-vbs
---
 SD-VBS/common/toolbox/toolbox_basic/spmtimesd.c | 141 ++++++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100755 SD-VBS/common/toolbox/toolbox_basic/spmtimesd.c

(limited to 'SD-VBS/common/toolbox/toolbox_basic/spmtimesd.c')

diff --git a/SD-VBS/common/toolbox/toolbox_basic/spmtimesd.c b/SD-VBS/common/toolbox/toolbox_basic/spmtimesd.c
new file mode 100755
index 0000000..a98dc0a
--- /dev/null
+++ b/SD-VBS/common/toolbox/toolbox_basic/spmtimesd.c
@@ -0,0 +1,141 @@
+/*================================================================
+* spmtimesd.c
+* This routine computes a sparse matrix times a diagonal matrix
+* whose diagonal entries are stored in a full vector.
+*
+* Examples: 
+*     spmtimesd(m,d,[]) = diag(d) * m,
+*     spmtimesd(m,[],d) = m * diag(d)
+*     spmtimesd(m,d1,d2) = diag(d1) * m * diag(d2)
+*     m could be complex, but d is assumed real
+*
+* Stella X. Yu's first MEX function, Nov 9, 2001.
+
+% test sequence:
+
+m = 1000;
+n = 2000;
+a=sparse(rand(m,n));
+d1 = rand(m,1);
+d2 = rand(n,1);
+tic; b=spmtimesd(a,d1,d2); toc
+tic; bb = spdiags(d1,0,m,m) * a * spdiags(d2,0,n,n); toc
+e = (bb-b);
+max(abs(e(:)))
+
+*=================================================================*/
+
+# include "mex.h"
+
+void mexFunction(
+    int nargout,
+    mxArray *out[],
+    int nargin,
+    const mxArray *in[]
+)
+{
+    /* declare variables */
+    int i, j, k, m, n, nzmax, cmplx, xm, yn;
+    int *pir, *pjc, *qir, *qjc;
+    double *x, *y, *pr, *pi, *qr, *qi;
+    
+    /* check argument */
+    if (nargin != 3) {
+        mexErrMsgTxt("Three input arguments required");
+    }
+    if (nargout>1) {
+        mexErrMsgTxt("Too many output arguments.");
+    }
+    if (!(mxIsSparse(in[0]))) {
+        mexErrMsgTxt("Input argument #1 must be of type sparse");
+    }
+    if ( mxIsSparse(in[1]) || mxIsSparse(in[2]) ) {
+        mexErrMsgTxt("Input argument #2 & #3 must be of type full");
+    }
+  
+    /* computation starts */
+    m = mxGetM(in[0]);
+    n = mxGetN(in[0]);
+    pr = mxGetPr(in[0]);
+    pi = mxGetPi(in[0]);
+    pir = mxGetIr(in[0]);
+    pjc = mxGetJc(in[0]);
+ 
+    i = mxGetM(in[1]); 
+    j = mxGetN(in[1]);
+    xm = ((i>j)? i: j);
+
+    i = mxGetM(in[2]); 
+    j = mxGetN(in[2]);
+    yn = ((i>j)? i: j);
+   
+    if ( xm>0 && xm != m) {
+        mexErrMsgTxt("Row multiplication dimension mismatch.");
+    }
+    if ( yn>0 && yn != n) {
+        mexErrMsgTxt("Column multiplication dimension mismatch.");
+    }
+    
+ 
+    nzmax = mxGetNzmax(in[0]);
+    cmplx = (pi==NULL ? 0 : 1);    
+    out[0] = mxCreateSparse(m,n,nzmax,cmplx);
+    if (out[0]==NULL) {
+        mexErrMsgTxt("Not enough space for the output matrix.");
+    }    
+   
+    qr = mxGetPr(out[0]);
+    qi = mxGetPi(out[0]);
+    qir = mxGetIr(out[0]);
+    qjc = mxGetJc(out[0]);
+    
+    /* left multiplication */
+    x = mxGetPr(in[1]);
+    if (yn==0) {
+        for (j=0; j<n; j++) {
+            qjc[j] = pjc[j];
+            for (k=pjc[j]; k<pjc[j+1]; k++) {
+                i = pir[k];   
+                qir[k] = i;
+                 qr[k] = x[i] * pr[k];
+                 if (cmplx) {
+                     qi[k] = x[i] * pi[k];
+                 }
+            }
+        }
+        qjc[n] = k;
+        return;
+    }
+    
+    /* right multiplication */
+    y = mxGetPr(in[2]);
+    if (xm==0) {
+        for (j=0; j<n; j++) {
+            qjc[j] = pjc[j];
+            for (k=pjc[j]; k<pjc[j+1]; k++) {
+                qir[k] = pir[k];
+                qr[k]  = pr[k] * y[j];
+                if (cmplx) {
+                    qi[k] = qi[k] * y[j];
+                }
+            }
+       }
+       qjc[n] = k;
+       return;
+   }
+    
+   /* both sides */
+   for (j=0; j<n; j++) {
+       qjc[j] = pjc[j];
+       for (k=pjc[j]; k<pjc[j+1]; k++) {
+           i = pir[k];
+           qir[k]= i;
+           qr[k] = x[i] * pr[k] * y[j];
+           if (cmplx) {
+               qi[k] = x[i] * qi[k] * y[j];      
+           }
+       }
+       qjc[n] = k;
+   }
+   
+}   
-- 
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